Magnetic chuck for a part having two magnetizable zones



p 1950 w. A. BOCKISCH 2,521,821

MAGNETIC CHUCK FOR A PART HAVING TWO MAGNETIZABLE ZONES Filed Feb. 16,1946 3 Sheets-Sheet 1 h ATTORNEY I Sept. 12, 1950 w. A. BOCKISCH2,521,821

MAGNETIC CHUCK FOR A PART HAVING TWO MAGNETIZABLE ZONES Filed Feb. 16,1946 3 Sheets-Sheet 2 Sept. 12, 1950 w. A. BOCKISCH 2,521,821

' MAGNETIC caucx FOR A PART HAVING TWO MAGNETIZABLE ZONES Filed Feb. 16,1946 3 Sheets-Sheet s Patented Sept. 12, 1950 MAGNETIC CHUCK FOR A PARTHAVING TWO MAGNETIZABLE ZONES Walter A. Bockisch, Elmhurst, IlL,assignor to a Western Electric Company, Incorporated, New

York, N. Y., a corporation of New York Application February L6, 1946,Serial No. 648,160,

This invention relates to an article working apparatus, and moreparticularly to a grinding apparatus having self-aligning chuckingmeans.

In the manufacture of some electrical apparatus, for example, magnetrontubes, magnetic and non-magnetic parts are welded or brazed together. Inthese welding or brazing operations the parts become displaced withrespect one to another in spite of attempts to maintain them in fixedpositions and accordingly some of the parts are purposely made oversizeand after assembly are ground to the desired size and contour. In thedisplacement occurring in the welding operations, surfaces which shouldbe maintained in a predetermined relation one to another are frequentlydisplaced and in the grinding operation considerable difiiculty has beenexperienced in providing means for holding the articles during thegrinding in such manner that undue stresses will not be applied to theassemblage.

It is an object of the present invention to pro- 4 Glaims. (Cl. 175-367)vide an article working apparatus capable of holding articles inposition to be worked without applying undue stress to the articles.

In accordance with one embodiment of the invention as applied to anapparatus for grinding surfaces of certain elements of magnetron tubesto the desired contour, self-aligning pole pieces are provided in spacedrelation one to another for engaging spaced areas of the article to beground in such manner that the faces of the pole pieces will alignthemselves with non-parallel surfaces of the article while othersurfaces of the article are being ground to the desired contour.

The self-aligning pole faces form part of the magnetic chucking deviceincluding a self-aligning by-pass element mounted upon a table movablelongitudinally and transversely beneath a grinding element andpositionable to present various surfaces of the article to the grindingwheel. In order to protect certain parts of the article from contactwith the grinding wheel during the grinding operation, a locking devicelimits the distance the table may be moved transversely while permittingfree longitudinal movement. In another position the locking devicepermits unlimited transverse movement of the table while thelongitudinal movement. is restricted.

A complete understanding of the invention will be. had by reference thefollowing detailed de-.

scription taken in conjunction with the accompanying drawings, whereinFig. 1 is a perspective view of a preferred embodiment of the invention;

Fig. 2 is a front view of a portion of the apparatus showing an articleheld in position by the;

magnetic chuck;

Fig. 3 is a sectional view of the apparatus taken substantially on theline 3-3 of Fig. 2 showing the relationship of the grinding wheel to thearticle being worked and the chuck, the article and the wheel beingshown in elevation;

Fig. 4 is a plan view of a portion of the appa-' I ratus shown in Fig.land illustrating the rela tionship of the by-pass element to themovablepole pieces.

Fig. 5 is a sectional view of the apparatus taken on the line 5--5 ofFig. l. with part shown in ele-.

vation; and I v Fig. 6 is a detailed view of a portion of the apparatustaken on the line 6-45 of Fig. 4. The embodiment of the inventiondisclosed herein comprises an apparatus for grinding an article ill inwhich distortion or deformation may not be tolerated, and whichcomprisesa central It will be seen from the drawings that the ap-'-' paratus isprovided'with a base 20 having an uprightstandard 2| adjacent the upperend of which is mounted a grinding wheel 22 that may be driven by anysuitable means (not shown). The base 2b is further provided with ways 23and 24 upon which a platform 25 is slidably mounted to guide theplatformduringtransverse position ing movement thereof in the directionsindicated by thedouble-hea'ded arrow 29. Ways 3i) and 3| at right anglesto the ways 23 and 24 are provided on the platform 25 to slidablysupport and guide a table 3'2 longitudinally movable in the directionsindicated by the double-headed arrow 33.

During the grinding operation for which this. apparatus was specificallydesigned. the trans- A plurality of fins verse movement of the apparatusin the directions indicated by the arrow 29 is limited while thelongitudinal movement in the directions indicated by the arrow 33 isunrestricted within the limits of the machine. These movements are underthe control of a locking mechanism 34 comprising a locking member 35fixed to a shaft 45 which is journalled in a plate M. A manuallyoperable lever 42 is secured to one end of the shaft 48 While aneccentric cam 43 is fixed to the other end thereof with its greatestradius pointing in the same directionas the locking member I 35. When ina: downwardi positio-Ir, theqlocki'ng" member 35 is limited in its areaof travel by stops 44 and 45 on a plate 50 fixed to the base 28.Directly above the cam 43 and at right angles to the shaft 45 a pin isslidablypositionecbin-an aperture 52 formed in the plate 4|.

While the"- article In is within range of thegrindingwheel 22 the upperend of the pin..5-l;' abutsahianglia;

member 53 secured to the table 32, imwhich-posi tion the pin 5| isunable to move upward thereby restricting the movement'ofthe cameoamholding locking member in its downwardposhtion. However, when the table32 has been movedto the right (Fig, ljifar. enoughto uncover thepin' 5|,the lever'42. maybe operatedto rotate the 1o'cking'member'35' upward andouter rangeof the stops 44 and thus permitting-transverse movement alongthe directions indicatedby the arrow 29 while the longitudinalmovement'of the apparatus is restricted b-y'the extension of the pin 5! into thepath of the angle-member 5-3;.

Secured to the table 32 is a plate- 5 made of magnetic. material, whichserves? as a base for a magnetic chuck' 55'. A suitable electromagnet 56with a. core 51- havingtwo pole pieces 55' and- BI is mounted on theplate 54 in such a manner that a face. 62" of the pole piece 5|intimately engages the plate to. provide a magnetic pathfrom the pole.through the plate. A stopor positioning member'63 is secured to thepolepiece 6G" to .aid. in. aligning the article. Ill being worked onaswill be described more indet'ail hereinafter The pole piece isprovided with an irregular shaped; magnetic extension 65 which hasformed therein a substantially semi-circular. channel 65' (Fig. 3-) to.slidably accommodate. asubstantiall y semi-cylindrical chucking member'Hl'. made of.

the: member 14 and. clamping. it at any desired height by means of,aclamping screw-18 which threodedly engages'a split. clamping'section19:02--

theiflxture 122 To facilitate adjustment, a helical compression springdisposed in a: hollow 8| formed. inthe lower end of the cylindricalmember 14 continuously urges the member 14 upward, the upwarddisplacement-g. however, reaching its limit when; an annular flange 82at the lower end of the member'14" abuts a circular When the article IDis placed in the chuck 55 for the grinding operation, the end blocks l2and I3 of the article [0 lie on the block 10 and the member 16,respectively, and the flange I5 is moved to engage the stop orpositioning member 63 thus to locate the article in proper position onthe chuck. After the electromagnet 56 is energized, the chucking members10 and I6 orient themselves so that the faces H and Ti intimatelyengage, by magnetic attraction, the end blocks l2 and [3, respectively.The magnetic attraction. between. the; chucking. members; '10 and I6andl. the end' blucksf l2 and I3 of the article is increased bycompleting the magnetic path around the non-magnetic central portion Hof the article through a magnetic by-pass element 84 made of magneticmaterial, which is rcsilientl'y' mounted on a non-magnetic support 85 bymeans. of a bolt-ain which passes through a double-cone-.shapedtaperture81 formed in the bodyrof therby-passielement and is threaded into thesupport. 85 The double-cone shape of the aperture?! aids inall gnment bypermitting a slight universal movement of the by-pass element. Rotationof the byjpass element 84 about thebolt. 86 isyprevented a guide.pin.,BD,. the

upper end. of which engages the. walls, of..a.slot. 9| formed in the.btt-Pflfiselenient- 84 and. the.

lower end orwhich. is secured to the. support member 85. The by-pass.element is urged resiliently upward by a helical compression spring 52which. encircles the. bolt 86* between the by.-

thehead. 1.0.0: 013- thebolt 86i The by -passe element'fld is: provided.with two,

40 cup-shaped soclsets I01 and Llll-zwhichaccommos shoulder 83: formedby an enlargement of the lower-'end'o'f' the bore" 13: To provide amagnetic pathffrom the magnet: to? the member 1 3;. the

fixture 1:2 the member 141 and the member 1-6 shoul'd be' made or:magnetic. material:

date substantially; hemispherical. members 03.

and; lil4--made: of magnetic material having arthe; bypass element. isnot. magnetically eneiw gized,,tlre members.- lll3; and- I04 areheldinplace. by headed bolts. 5% (-Fig s-.. 2 and 4) which pass throughshouldered: apertures: M It formed in the 1 members and; are threadedinto the body of the by--pass-v element. The apertures. HI. are slightlylarger than the-diameten of the bolts to effect auniversaljointbetween-the members llla and. H14 andthesockets H11 andI02, respectively.

To. obviate the possibility of. damaging the fins l4 andthefiangelfiwhilethe surface I'tis being; ground, the chuck. 55-is restrictedtojust enough transverse movement. to-permit'thev surface to be,

ground. Excessive transverse. movement is preventedihy the stops-44- and45. (Fig. 1.) secured Obviously; to? grind. the: other sunface it, it isnecessary totransversely shift. the chuck and; the article-a.glteatenougn distance to bring; the.

surface IB- within range. of. the: grinding: wheel This is accomplishedibymoving the tablev 32 to the. right (Fig... 1 untilthe angle member53-110. longer obstructsv the pin' 51-. thereby freeing,- the; cam 43and allowing the shaft 40 to be operated:

counterclockwise r tee raise the. 1.0 cking; member 3 5A.

In this position the article ID and the chuck are The lever 42isthen'operated to bring thelocking member 35 i into a downward orlooking position and to ermit the pin to drop, thereby freeing the table3! for longitudinal movement to the left (Fig. 1) to carry the surface I5 under the grinding wheel. In this position transverse movement islimited in one direction by the stop 45. No limitation is imposed in theother direction since there are no extensons or projections of thearticle it that could be damaged by movement in this direction.

In the operation of this apparatus the table 32 is moved to the right(Fig. 1) to a point just beyond the position illustrated in Fig. 1thereby removing from the pin 5| the restriction imposed by the anglemember 53 and positioning the chucking members and 16 well out of rangeof the grinding wheel 22. An article ID to be worked on is placed inposition upon the chucking members 10 and 16. The electromagnet 56 isthen energized to furnish magnetic force at the article engaging faces Hand 11 to firmly hold the article l0 by magnetic attraction. In thelongitudinal position just described, the chuck 55 may be movedtransversely to position either one of the surfaces l6 or I! forgrinding by simply operating the lever 42 counterclockwise, therebyrotating the locking member 35 toan upward position, thus permittingunimpeded transverse adjustment of the platform 25. It will be apparentthat upon clockwise rotation of the lever 42 not only is the lockingmember 35 rotated upward but the cam 43 also is rotated, thereby cammingth pin 5! upward and into the path of the angle member 53 and preventingaccidental longitudinal shifting of the table 32 to the left, thusprotecting the article Ill from the grinding wheel 22 during thetransverse shift. When the chuck 55 is in its proper transverse positionthe lever 42 is operated in a clockwise direction to rotate the lockingmember 35 downward and the cam 43 then permits the pin 5i to drop out ofth path of the angle member 53. If the chuck 55 has been transverselypositioned to permit the surface I! to be ground first then the lockingmember 35 will fall between the stops 44 and 45, thus limiting theaction of the grinding Wheel to the area bounded by the lines indicatedat l2 (Fig. 3), the distance at l2 being the same as that between thestops 44 and 45. The table 32 is then shifted to the left to subject thesurface I! to the action of the grinding wheel 22. It will be apparentthat in this position accidental transverse shifting of the chuck is notpossible because the angle member 53, by obstructing upward movement ofthe pin 5 I, prevents counterclockwise rotation of the cam 43 and thelocking member 35. In order to grind the surface IS the table 32 isshifted to the right until the left end of the angle member 53 is clearof the pin 5|, whereupon the lever 42 is operated counterclockwise tounlock the locking mechanism so as to permit a transverse shift toposition the surface 16 in line with the grinding wheel. In thisposition, if the lever 42 is rotated 6 clockwise; the locking me Toperform thegrin'ding operation on the surface [6 the table 32 isagainmoved to the left bringing the surface within range of the grindingwheel; i. I

While in the specific embodiment of the'inven-' tion disclosedherein anapparatus has been described which is adapted to work on an article'cornpo'sedof magnetic materials spaced apart by a non-magnetic sectionit will be obvious that the article worked could be made entirely ofmagnetic material, thus obviatingthe' necessity of using the icy-passelement.

What is claimed is:

1. A magnetic chuck for holding an article having isolated magnetizablesections, said chuck comprising a magnet having two poles, one of saidpoles being provided with a self-aligning face capable of unlimitedmovement around one axis, the second of said poles being provided with aself-aligning face capable of universal movement, each of saidself-aligning faces being adapted to engage a different magnetizablesection of said article thereby to cooperate in holding said articlewithout appreciably distorting or deforming it, and a magnetic by-passelement adapted to engage the separate magnetizable sections engaged 'bysaid faces, thereby to complete a low reluctance magnetic path, saidby-pass element having a self -aligning face member capable of universalmovement.

2. An apparatus for holding an article having isolated magnetizablesections, said apparatus comprising a pair of magnetizable chuckingmembers, one of said chucking members having a movable self-aligningarticle engaging surface, said chucking members being adapted to eachengage a different magnetizable section of said article, means forsupplying magnetic force to said chucking members, and a magneticby-pass element engageable with the sections of said article engaged bysaid chucking members thereby to form a low reluctance path between saidsections, said lay-pass element having a movable self-aligning articleengaging surface.

3. A magnetizabl chuck for holding an article having substantiallyisolated magnetizable portions, said chuck comprising an electromagnethaving oppositely magnetizable poles each having an article engagingface, one of said faces being movable with respect to its pole, each ofsaid faces being adapted to engage a separate magnetizable portion ofsaid article and said movable face being adapted to align itself withsaid article by magnetic force in response to contact with amagnetizable portion of said article, and a magnetizable by-pass elementadapted to intimately engage the magnetizable portions engaged by saidfaces thereby to form a low reluctance magnetic path between thelast-said portions.

4. A magnetizab-le chuck for holding an article having substantiallyisolated magnetizable portions, said chuck comprising an electromagnethaving oppositely magnetizable poles, each having an article engagingface adapted to engage a separate magnetizable portion of said article,and

a magnetic by-pass element having article engaging faces adapted toengage the magnetizable sections of the article engaged by said polefaces thereby to form a low reluctance path, one of the article engagingfaces on said icy-pass element being movable with respect to saidicy-pass element and adapted to align itself with respect to ber 35willfall between the stop 45 and the back of the apparatus, Fig. 1.

s Karmic Aug. 12, mm-

S1mnumsa June 15:..192IE Simmons? Sept. 2;, 1924s Hirst Dem271l92'7:

' Thompson Oct; 21, man

Chanik. Ap1:. 12; 1938? Brownietzal Apt: 25;.194!

Wuodhury 11,. 1945-1 FOREIGN PATENTS Country.- Date.

Great Britain; Feb 28; 1918

